Intruder mobility in a vibrated granular packing

TL;DR

This study experimentally investigates how a dense intruder sinks in a vibrated 2D granular packing, revealing flow patterns, effective friction, and a transition to intermittent dynamics near jamming, suggesting non-local rheological properties.

Contribution

It provides new experimental insights into intruder dynamics, flow rules, and non-local rheology in vibrated granular materials near jamming.

Findings

Identification of flow patterns around the intruder.

Observation of a transition to intermittent dynamics near jamming.

Evidence of non-local rheological behavior in vibrated granular packings.

Abstract

We study experimentally the dynamics of a dense intruder sinking under gravity inside a vibrated 2D granular packing. The surrounding flow patterns are characterized and the falling trajectories are interpreted in terms of an effectivive friction coefficient related to the intruder mean descent velocity (flow rules). At higher confining pressures i.e. close to jamming, a transition to intermittent dynamics is evidenced and displays anomalous "on-off" blockade statistics. A systematic analysis of the flow rules, obtained for different intruder sizes, either in the flowing regime or averaged over the flowing and blockade regimes, strongly suggest the existence of non-local properties for the vibrated packing rheology.}